Base for swivel chairs



Aug. 17, 1954 J. A. FITCH BASE FOR SWIVEL CHAIRS Filed Feb. 12, 1951 INVENTOR. 944;, 4. w.

ATTORNEYS.

Patented Aug. 17, 1954 BASE FOR SWIVEL CHAIRS Jason, A. Fitch, Lakewood, N. Y., assignorqtoArt Metal Construction Company,

Jamestown,

k N, Y.,, a corporation of New York Application February 12, 1951, Serial No. 210,558 3 Claims. (01. 24 -9194) l r This invention relates to: chairs and more particularlyto an improvednbase for swivel chairs. It is well known to construct the base of a swivel chair of sheet metal and desirably so ,because of its. rigidity,'durability and relative lightness. Usually included in such a chair base is a bearing sleeve which rotatably receives the spindle or swivel post of the chair. It is also common to construct swivel chairs so thati'the chair is capable of tipping backwardly to increase the comlikely to getout of orderlor require repairs.

Othe'robjects and advantages of'the invention will be apparent from the following description and accompanying drawings in which:

Fig. 1? is a top planview of a swivel chair base embodying the present. invention;

Fig. 2 is an elevationalfviewof ,the bottom thereof. t i t i Fig. 3 is a vertical longitudinal central sectional view thereof taken on line 3-,3,,'Fig. l.

Fig. 4 is an enlarged fragmentary view of the central portion of the structure shown in Fig. 3.

In accordance with conventional practice, a blank of sheet metal of suitable gauge and of proper size and shape from which to produce the chair base, is pressed or otherwise formed to comprise a central portion lfl'liaving radiating therefroma plurality of legs ll.

The legs II, which are duplicates of (meanother, are of substantially inverted u shape in cross section and are formed to terrriinatein downturnedterminal portions or feed l2. Casters (not shown) are adapted forconnection with the feet I 2 but inasmuch as this forms no part of the present invention such casters are not illustrated.

Each leg I l is inclusive of a top wall I3 and a pair of side walls 14, M and, as shown, the adjacent side walls of adjacent legs are formed as curved continuations of one another at the central portion of the structure, these curved continuing or connecting portions being designated at and defining'the width of the central portion 10 between the legs ll.

Preferably, as shown, the top wall l3 of each leg II is pressed to form alongitudinally extending scuif rib l6 at the outer end thereof to prevent marring of the top surfaces of the legs. These ribs l6. also serve to stiffen and reinforce the outer ends of the legs ll- .7

The top walls 13 of the legs H are integrally formed with a top plate or wall IB which covers the central portion Ill.

The lower edges of the side walls I4 of each leg I l is shownas joined by a lower plate I9 which is made lighter by cutting out an elongated opening 20 and also reinforced by forming the metal of the lower plate into a continuous bead 2| which surrounds the opening 20. The longitudinal edges of the lower plates 19 may be connected to the respective side walls M in any suitable manner as by welding. w 1 t H Enclosing the bottom of the central portion I0 is a central lower plate 22 which is shown as suitablyconnected to the inner ends of the lower leg plates I 9 and also to the curved walls 15. The central lower plate 22 is preferably dished downwardly as shown and also is formed with a series of radial reinforcing integral ribs 23. The disk-like center portion 24 of the central lower plate 22 is flat and horizontal and provided with a central hole or opening 25. i

i The top plate l8 of the center portion 10 is preferably offset downwardly at its center to provide a disk-like center portion26 which is flat and horizontal and has a central hole or opening 28 in registry with the lower hole 25.

A bearing sleeve 30 in the form of a cylindrical tube is shown as arranged between the upper and lower center portions 26 and 24 respectively. This bearing sleeve rotatably receives the spindle or swivel post (not shown) of the chair. The lower end of the bearing sleeve 30 is'reduced and extends througli the hole 25 in the central lower plate 22. The upper marginalsurface of the center portion 24 of this lower plate engages a downwardly facing annular shoulder 3| and is held thereagainst by peening or rolling the lower extremity of the bearingsleeve 30overlthe lower marginal surface of the center portion 24 as indicated at 32. In this manner the center portion 24 of the central lower plate 22 is firmly connected to the lower end of thebearing sleeve 30.

In a similar manner the upper end of the bearing sleeve 30 is reduced to provide an upwardly facing annular shoulder 33 and the upper extremity of this sleeve is peened or rolled over onto the upper surface of the center portion 26 of the top plate It as indicated at 34.

As conventionally practiced the lower surface of the center portion 26 of the top plate I8 directly engages the shoulder 33. In such a conventional construction it will be seen that the bearing sleeve 30 is solely supported by the marginal connections with the top plate [8 and central lower plate 22 and these plates are subject to flexure in a vertical direction and also to some lateral distortion, particularly the top plate l8.

In accordance with the present invention this undesirable condition is avoided by providing a bracing member 35 between the top plate it and central lower plate 22. This bracing member 35 is shown in the form of a frusto-conical sleeve member of sheet metal and the base of which bears against an abutment on the central lower plate 22 and the upper end of which is connected to the bearing sleeve 30. The upper end of the bracing member 35 is shown as formed with an inturned annular flange 36 which surrounds the reduced upper end of the bearing sleeve 39 and is arranged between the shoulder 33 and the center portion 26 of the top plate 22. The hole or opening 37 of this flange 36 closely fits the periphery of the reduced upper end of the bearing sleeve 30. From this annular flange as the bracing member 35 flares downwardly and outwardly and the lower rim portion is preferably outturned to provide a continuous annular lip 33. This lip 33 abuts the inwardly facing surface of an upstanding annular bead 355 which is formed in the central lower plate 22. Instead of the continuous bead 353 other types of abutments may be provided on the central lower plate 22.

Referring to Fig. 2, it will be seen that portions of the annular bead 39 are adjacent the curved side wall portions l of the central portion Ill of the base structure and hence there is rigid support for this bead both vertically and laterally.

It is to be noted that there is no connection between the lower end of the bracing member 35 and the central lower plate 22 other than an abutting engagement between the annular lip 38 and bead 39. As to the upper end of the bracing member, the flange 36 thereof is caught between the center portion 26 of the top plate is and the shoulder 33 on the bearing sleeve 30 so that special fastening elements are not required to mount the bracing member 35 of the present invention in the shell of the chair base.

In assembling a structure embodying the present invention, the bracing member is first arranged against the top plate l8 and the upper reduced end of the bearing sleeve is inserted through the registered holes 25 and 31. ing this the central lower plate 22 is placed over the lower end of the bearing sleeve 30, the lip 38 bearing against the inwardly facing side of the annular bead 39. The extremities of the bearing sleeve 30 may then be peened over to firmly lock the parts in place and, of course, the outer margin of the central lower plate 22 is suitably connected to the adjacent parts.

From the foregoing it will be seen that the present invention provides a reinforced sheet metal swivel chair base which is simple in con- Followstruction, easy to assemble and inexpensive to manufacture.

I claim:

1. In a sheet metal base for swivel chairs having a central portion including spaced upper and lower plates and a bearing sleeve arranged therebetween and connected at its lower end to said lower plate, said bearing sleeve having an upwardly facing shoulder adjacent its upper end above which said top plate is arranged, the combination therewith of bracing means comprising a sleeve member surrounding said bearing sleeve and having at its upper end an inturned flange arranged between said top plate and shoulder, means holding said top plate and flange against said shoulder, said sleeve member flaring downwardly and outwardly from said flanges and an annular abutment on said lower plate, and continuously engaging the lower rim of said sleeve member.

2. In a sheet metal base for swivel chairs having a central portion including spaced upper and lower plates and a bearing sleeve arranged therebetween and connected at its lower end to said lower plate, said bearing sleeve having an upwardly facing shoulder adjacent its upper end above which said top plate is arranged, the combination therewith of bracing means comprising a frusto-conical sleeve member surrounding said bearing sleeve and having at its upper end an inturned flange arranged between said top plate and shoulder, means holding said top plate and flange against said shoulder, the lower end portion of said sleeve member being outturned to provide an annular lip, and an annular abutment upstanding on said lower plate and surrounding and continuously engaging the rim of said lip.

3. In a sheet metal base for swivel chairs, the combination comprising upper and lower plates, a bearing sleeve arranged therebetween and connected at its lower end to said lower plate and at its upper end having an annular groove, said top plate having an annular portion arranged in said groove and closely fitting the base of said groove, a reinforcing sleeve member arranged between said plates and surrounding said bearing sleeve and having at its upper end an inturned annular flange arranged in said groove below said annular portion and closely fitting the base of said groove, said sleeve member flaring downwardly and outwardly from said flange, an annular abutment on said lower plate and continuously engaging the lower rim of said sleeve member, and a series of reinforcing ribs on said lower plate between said bearing sleeve and said annular abutment and radiating outwardly relative to said bearing sleeve.

References Cited in the file of this patent UNITED STATES PATENTS Michelson Mar. 17, 1942 

